Internal combustion engine



Jan. 28, 1936. Y. HIRONAKA INTERNAL COMBUSTION ENGINE Filed. June' 15,'1932 FIG. I.

l I l Full Over

LOAD

Patented Jan. 2s, 1936 PAT-ENT OFFICE 2,029,169 INTERNAL coMBUs'rIoN ENGiNE Yasusaburo Hironaka, Tsuwano-cho, Kano-Ashigun, Shimane-ken, Japan Application June 13, 1932,' Serial No. 617,006

4 Claims.

This invention relates to improvements in internal combustion engines, and has for an object' to provide a means whereby, by altering or regulating the spacial volume of the explosion-chamber oi the engine in accordance with the load,

I the compression ratio can be controlled to a certain degree. Another object of the invention is to enhance, Vunder any conditions of load, the thermal eftlciency'of the engine by regulating the pressure of compression in such a manner that it may become most adapted for the state or 'nature 'of the combustible mixture, throughout the varying circumstances of the load.

The invention is hereinafter described with reference to the accompanying drawing, in

whichz p Fig. 1 is a sectional elevational view of an internal combustion engine embodying the present invention;

Fig. 2 is an enlarged view of the piston of the I0 and I0" respectively, the said pawl device engine, shown in side elevational section;

Fig. 3 is a front elevational, vpartly sectional, view of the engine, showing'particularly the automatic regulating device when it assumes a posi- 'tion forincreased compression ratio;

Fig. 4 is a view showing a particular part of the automatic regulating device when it occupies a position for reduced compression ratio;

Fig. 5 is a view showing the particular part of the automatic regulating device when it assumes a, position for maintaining the compression ratio constant; and l Fig. 6 is a diagram showing inY comparison thermal efiiciencies. Curve #l represents that 'of an engine accordingto the present invention while curve #2 indicates that of the ordinary Otto-cycle motor.

Fig. 1 is a detail view of the manual operating means. Y

Similar numerals denote similar parts throughout the several iigures.

Referring to the drawing, the piston I has apiston-pin I around which is fitted an eccentric hub 2 to which is rotatably attached the piston end of the connecting rod-20 of the piston, the axial line :i1- of the eccentric hub being displaced from the axial line y-y of the piston-pin by an eccentricity, say, C. lThe eccentric hub 2 is formed at one end with a worm-gear 2 which is concentric with thepiston-pin I and engaged with a worm 3 the lower end of which is connected with abar 3' which is square in section.V Adjacent to Ithe lower end of the square bar 5 there is mounted thereon a worm-gear 4 which is sldable along on the former by `means of its explosive mixture, described.

square opening which isformed to coincide with the sectional dimensions of the square bar 3', the said worm-gear 4 being engaged with another worm-gear 5 supported by a bracket 6. The arrangement of the square bar is such that when 5 the piston I is set in motion the former is actuated by the latter so as not only to rotate but to slide along through the opening through the worm-gear 4. A shaft 1 on which is mounted the worm-gear 5 projects outwards from the casing 10 8 of the engine, this shaft being so disposed that it may be either rotated by an automatic device or by hand. The device for automatically rotating the shaft 1 is illustrated in Figs. 3 to5 inclusive, which 15 consists of an arrangement of parts 'as described below. To the portion of the shaft 1 projecting outside the casing of the engine, there is attached a gear-wheel 8 which is adapted to be engaged by a pawl device I0 having two iingers 20 may be conducted to a plunger I6 through a 30 non-return valve I5. The plunger I6 is fln'nished with a spring I1 which is supported by an abutment I8 and adapted to oppose the pressure of the said plunger, while one end of the plunger is pivotally connected with the pawl device Ill. 35 If a hand-manipulated system is preferred, the shaft 1 may be rotated simply by a hand-lever I9 attached to the said shaft, as shown in Figs. 1

and '1.

-The automatic device for rotating the shaft 1, 40 referred to, is operated as iollowsz- It is understood that the engine is equipped with a suitable governor to control the supply of which need not be shown or When the load on the engine is diminished the governor is actuated and accordingly causes a decrease in the admission of the fuel mixture charge or allows a leaner mixture to be admitted,l the maximum explosion pressure of the engine is lowered and this results in a reductiondn the pressure acting on the plunger I6, thereby making the latter .unable to balance the pressure of the spring I1 any longer. Thereupon the pawl device I0 assumesa position as shown in Fig. 3, permit- 55 pression ratio of the engine. Therefore, the output of the engine is enhanced, resulting in an increase inthe speed of rotation. Now the governor is vactuated so that it follows that the leaner the composition cthe admitted. mixture grows th@ greater the maximum explosion pres-.

sure of the engine becomes. If the maximum explosion pressure rises to a pre-determined value, or also if a premature ignition takes: place, allowing -the pressure acting on the plunger I6 to overcome the compression of the spring l1, the pawl device l will assume the position Vas illustrated in Fig. 5, thereby bringing the operation of vthe compression regulating device to a stop. The engine will then commence to work at a constant degree of compression (namely, a value of compression ratio in proximity to the highest possible ameunt of such value obtainable under the circumstances, subject'to load, etc.).

On the other hand, as the load of the enginebecomes greater, the governor is actuated, pernetting thereby a richefmixture to be aemitted and accordingly increasing the uid pressure acting on the plunger i6, the balance of forces set np ,between the latter: and the spring l1 thereby being destroyed, and forcing the pawl device l0 to assume a position diilerent fromthat referredr to hereinbefore, while the upper paw or linger I0 of the pawl device comes into action as shown inl Fig. 4. Therefore,- the compression regulating device is actuated to more in the direction contrary to that referred te above. Now, as the maximum explosion pressure isA lowered by degrees,a correspondingly gradual decrease in the iiuid pressure acting on theplunger I6 takes place, the said pressure therefore the compression regulatingI device toresume the position, as illustrated in Fig. 5.

To provide positive operation throughout the stages of operation hereinbefore described, it is necessary that the pressure of the burned gases prevailing in the space between the non-return valve I and the plunger I6be suciently high to allow for losses by contraction of the said gases due to ceoling, leakage aroundthe plunger and so forth.

Where the hand-manipulated device is used, the compression ratio may be regulated by rotating the hand crank I 9 and altered to such a value as desired, provided that the same may not I exceed the of twice the radius of eccen-v tricity.

'l It is understoodpthat .the Ithermal eiiiciency of an internal combustion engine is determined largely by the pressure attained during the compression stroke of the engine. With regard to the known Otto-cycle engine, it has however been necessary that the degree of the compression ratio be based on overload condition, or, in other Words, limited withinsuch a safe-range of values as will not cause a premature ignition or detnation, even though the engine is workedratv an .overheated temperature and with the full admission of a rich mixture, and, for that reason.

balances the -compression of the spring I1, and allows thereby it has been the practice that the engine of that type be operated at a relativel),T low compression ratio when compared with the iesel engine. In actual cases, it has been diihcult to make engines of the Otto-cycle type attain a compression ratio higher than 6-1.v AThe fact is"`obvious that the Otto-cycle engine does not attain its maximum permissible pressure even at a full'- load. y

It is further pointed out, from the theoretical point of view, that, in order to produce-as much work as possible from the admitted charge, the

Otto-cycle engine should have a higher compression ratio at reduced loads than at a full load, inasmuch as the governor comes into operation so as to diminish the a'mountf of the fuel mixture charge admitted or make the composition or the same leaner. It is tobe noted that lean mixtures do not at all cause illeiects such as detcnat'ion,.premature ignition and so forth, even if the engine is operated at a compression ratio from 10 to 1 to 13 to 1. Experiments have shown that thermal emciencies developedin such cases are considerably higher than'l those obtained by subjecting rich mixtures to low. pressure. or

t the eiiiciencies obtained atfull load. It is' admitted that the compression ratio of en engine at reduced loads is considerably lower` than that necessary for the maximum compression pres-'\ sure because of the constant fixed volume of the combustion chamber (that is, the minimum volume ofthe combustion chafmb-er which is permissible at an overload). Accordingly, it would be expected that the engine of the Otto-cycletype should have thermal efciencies higher at reduced loads than at full loads. However, actually the converse is the case, and such thermal emciencies become lower at. reduced loads, as dlagrammatically illustrated in Fig. 6. This fact seems to be one of the outstanding drawbacks of v theOtto-cycle engine.

According to this invention, however, means is provided so that the compression ratio may be regulated either. automatically or by hand in.

such a manner that the engine can be operated at all times at a compreion ratio which is in proximity to the highest possible ratio obtainable tnder the circumstances, subject to conditions c-f load, richness of the fuel mixture, tem= perature of the engine, and so forth. Asa result, the thermal eillciency is enhanced throughout the varying ranges of the load, l

when the engine is operated at reduced loads, as indicated in Fig. 6.

It has been found that fuels of inferior qualities such as heavy-oils are not adapte-d for use in engines of the Otto-cycle type. because of the fact that they cannot be gasiied with ease either at atmospheric or at slightly raised temperatures.. According to this invention, it is vpossible to make use of fuels Adi? this and such fuels, which are admitted in the form of mixtures while retaining a spray-like state, are subjected to high pressures and thereby thoroughly gasied at relatively high temperatures so as to inally eiect a self-exp-osion. In this respect, it

entirely dispensed with in the invention.

One of the eases where the invention can be 'advantageously carried into' eiiect is'engines for is to be noted that the usual ignition device is ated at reduced eiciencies. The present invention appropriately overcomes such disadvantages and brings about considerable increases in the thermal eiiciency as Well as the economy in the consumption of fuel, by ensuring an efficient degree of the compression ratio in accordance with the changes in the loads and speeds of crankshaft' rotation.

I claim:

l. In an internal combustion engine, having a frame, a piston, a piston rod, a piston pin carrying an eccentric'hub connecting the piston and piston rod, the combination of means for rotating said hub in opposite directions to vary the stroke of the piston and compensate for variations of pressure in the engine, said means comprising a transverse shaft mounted on the engine frame, a ratchet Wheel mounted on said shaft, a paWl device engageable with said ratchet wheel and constructed and adapted to turn said ratchet wheel in alternately opposite directions, means operable through the rotation of said ratchet wheel to rotate the said eccentric hub to different positions and means controlled by variations of pressure in the engine for actuating said pawl device.

2. In an internal combustion engine having a frame, a cylinder, a piston, a piston pin, a connecting rod, the combination of an eccentric sleeve rotatively mounted on the piston pin and carrying one end of the connecting rod, a worm gear concentric with the piston pin, a worm with which said Worm gear engages, a vertical shaft carried on the engine frame and by which said worm is supported and which is vertically movable and axially rotatable, a transverse shaft mounted on the engine frame, a Worm carried by said transverse shaft, a worm gear having a central opening through which said vertical shaft extends and is movable lengthwise, said last named worm gear being in rotatable engagement with. said vertical shaft and means controlled by variations o'f pressure in the engine for rotating said transverse shaft alternately in opposite directions and thereby altering the throw of the piston to compensate for said variations.

2. An internal combustion engine, comprising a frame, a cylinder, a piston reciprocable therein, a piston rod, a piston pin and a crank shaft, the piston pin being provided with an eccentric sleeve embraced by the piston rod and the said sleeve being provided at one end with a worm gear concentric with the piston pin, a worm with which said Worm gear is engaged, a squared rod on which said Worm is mounted and which is rotatably carried by the piston and movable lengthwise therewith, a second worm gear mounted on the engine frame and having a central square opening through which said squared rod is slidable, a transverse shaft mounted on the engine frame, a worm fixed on said shaft and engaging with said second Worm gear, a gear Wheel carried by the last named shaft outside the engine frame, means responsive to variation in pressure in the engine for rotating said last named shaft in alternately opposite directions and thereby altering the throw of the piston to compensate for variations in said pressure.

4. In an internal combustion engine, including a cylinder and piston, means for varying the throw of the piston under variations of pressure in the cylinder, including a shaft, a ratchet wheel mounted thereon, a pawl device for turning said shaft in alternately opposite directions and means for actuating said pawl device and turning said ratchet wheel in a direction dependent on the Variation of pressure in the cylinder.

YASUSABURO HIRONAKA. 

